Well my Pentas are now looking nice and clean - Lysol kitchen cleaner spray, followed by Duraglit metal polish/cleaner was the answer to the cosmetic issues, thanks everyone!

 But one of them doesn't sound so good... turns out the reason for this is, only the midrange speakers are producing any sound. I'm not remotely familiar with Pentas, or indeed any of the B&O powered/active speakers... any suggestions where to start? I'll have a google myself, but any pointers to online service manuals or disassembly guides would also be helpful.

 Thanks

Mike
 

If you pay for the silver or gold membership you'll have access to the penta service manuals which show the full disassembly and schematics.

As for your actual issue:  The pentas use two separate circuit boards for the crossovers.  One board handles the midranges and the other handles the tweeter and woofers.  If you're certain that only the midranges are working, then I'd suspect at some point you may have gotten a loose connection going to the one crossover circuit board that handles the tweeter and woofers.

Austin

camshaft:

If you pay for the silver or gold membership you'll have access to the penta service manuals which show the full disassembly and schematics.

As for your actual issue:  The pentas use two separate circuit boards for the crossovers.  One board handles the midranges and the other handles the tweeter and woofers.  If you're certain that only the midranges are working, then I'd suspect at some point you may have gotten a loose connection going to the one crossover circuit board that handles the tweeter and woofers.

Austin

 Thanks for that, sounds like it could indeed be a bad connection in that area - or indeed a bad board, I suppose; it's for sure there's no sound coming from anything except the midranges (which also need refoaming, but that's no big deal, the foams are on order).

 As for the manuals, are there no free resources? In the old computer world, we have bitsavers, which is all free:

http://www.bitsavers.org/
 
" As of Mar, 2008 there are over 13,300 documents containing over 1,228,400 pages in the archive."

 I'll probably stump up for the silver membership anyway! :-)

Thanks

 Mike

corestore:

As for the manuals, are there no free resources? In the old computer world, we have bitsavers, which is all free:

 I'll probably stump up for the silver membership anyway! :-)

Thanks

 Mike

Hi Mike,

            in an ideal world the manuals would be free for download. However Beoworld requires funding and to obtain part of this we offer the use of this database along with other benefits to silver & gold members as a way of thanking them for supporting the site financially. The other (easy & proftable) alternative would be to give in to advertising and have ad's popping up all over the forum. This option is definately NOT what we want for Beoworld.

Chris.

Well I signed-up for silver membership, and the manuals proved helpful... removed the amp and base, wiggled the connectors on the tweeter/woofer board, and normal service was restored. So we have a fairly nice working set of sub-$500 Pentas

Frustratingly the speaker went back to midrange-only when restored to a vertical position, a judicious slap to the cabinet restored the tweeter and woofers, but alas only temporarily. Must be a dry joint or else I didn't clean the contacts well enough - doesn't matter, it's only a matter of patience now, I'll nail the bugger permanently!

Thanks to all.

Mike 

You can also just cut off the contacts and solder the bare wires.  That should help the issue.

Austin

The good news is it isn't serious. Dry solder joint sounds favourite to me, maybe it would be worth replacing the capacitors while your at it? I did this with some MC120.2s and the improvement was very noticable.

Chris.

I agree with Chris. Many owners are in for a huge surprise when replacing the old capacitors. Electrolytic capacitors only have a limited life span, maybe 20 years and, let's face it, both the years and the caps have gone by now. New caps will restore the original sound and we can take it even further with the Penta's;

A Beolab Penta upgrade kit is in the making, almost ready. Amongst many other things, it also takes care of the crossover capacitors and that to an audiophile grade.

Martin

Dillen:

I agree with Chris. Many owners are in for a huge surprise when replacing the old capacitors. Electrolytic capacitors only have a limited life span, maybe 20 years and, let's face it, both the years and the caps have gone by now. New caps will restore the original sound and we can take it even further with the Penta's;

A Beolab Penta upgrade kit is in the making, almost ready. Amongst many other things, it also takes care of the crossover capacitors and that to an audiophile grade.

You make it, I'll buy it. I pulled the amp off again, cleaned and nipped-up all the crossover connectors, and everything seemed fine and stayed fine. I put on one of my favourite tests - the last ten minutes of side one of 'Tubular Bells' - the bit that starts with five minutes of extreme bass workout. Cranked it up to 85. Small objects fell off nearby shelves, and at least three flies who strayed too close to the woofers died horribly, but there were just a couple of microscopic crackles from the previously-sick speaker. A pretty convincing performance.

These are the best speakers I've ever personally owned; if they sound like this after a quick fettling, Goddess only knows what they'll sound liked when re-foamed and re-capped!

If I can drift the thread slightly (hey I started it!), what are considered the best speakers to take advantage of the full 4 Ohm / 150W performance of the Beomaster 8000? And what was the general opinion of the quality of the Beolab/vox 5000 flat panel speakers? 

Mike
 

MS150's are often touted as being the best passive speakers ever built by B&O and are the recommended ones for the Beomaster 8000. Most will now require refoaming of the Bass & Midrange drivers though if not already done. They tend to be quite expensive even in poor condition. If you find some (as with all this speaker range) always check that the drivers haven't been replaced with so called equivalent ones as they won't perform as intended, the drivers were specifically manufactured to B&O spec's and are impossible to replace with anything other than originals. You're far better off with ones with foam rot and getting them repaired. Again I would definatley change the capacitors as a standard operation.

The flat panel 5000's are also excellent speakers and have been the subject of many heated "5000 V's Penta" threads on Beoworld with the outcome almost always split 50/50 amongst the membership.

Chris.

Medogsfat:

MS150's are often touted as being the best passive speakers ever built by B&O and are the recommended ones for the Beomaster 8000. Most will now require refoaming of the Bass & Midrange drivers though if not already done. They tend to be quite expensive even in poor condition. If you find some (as with all this speaker range) always check that the drivers haven't been replaced with so called equivalent ones as they won't perform as intended, the drivers were specifically manufactured to B&O spec's and are impossible to replace with anything other than originals. You're far better off with ones with foam rot and getting them repaired. Again I would definatley change the capacitors as a standard operation.

The flat panel 5000's are also excellent speakers and have been the subject of many heated "5000 V's Penta" threads on Beoworld with the outcome almost always split 50/50 amongst the membership.

Thanks for that Chris, I'll keep an eye out for a set of MS150s (that was the M150 with added subwoofer, IIRC).

Penta vs. 5000 is interesting... my main room speakers for the past... nearly 15 years now!... have been a pair of Beovox 5000s. Now they don't stand up to critical comparison with real audiophile-grade gear, although I still like how they sound, but having now had a little time with the Pentas I have to say they blow the 5000s away. Now that's not a fair comparison, since the Pentas are labs, but (being on a slight fixer-upper spending spree just now) I've just gone out and spend $500 on a pair of Beolab 5000s, very nice condition but one of which is suspected to a have a faulty amp (intermittantly won't power on). Once I've fixed them up I'll give them a comparison test!

Mike
 

Hi Mike,

Are you talking about those beolab 5000's that were on ebay and didn't sell for his starting price of $600?  I was tempted by those also, but I've got too much on my plate to worry about right now.

Chris, is the comparison between the 5000's and the pentas really split 50/50 between the members?  I always thought it was Graham(Joeyboygolf) vs. everyone else 

camshaft:

Hi Mike,

Are you talking about those beolab 5000's that were on ebay and didn't sell for his starting price of $600?  I was tempted by those also, but I've got too much on my plate to worry about right now.

Those are the ones I bought; the guy was not too far away so we met half-way and did the deal. $500.

Actually, they're both dead; one fails to power-up, as advertised - no red light. The other... has a red light, when given a signal (Powerlink), the red light goes out. No sound. The display backlight comes on, but nothing is displayed. No criticism of the seller; he had no B&O gear to test them with. Hopefully I can fix them. If not... well I'm not complaining, I've got a set of perfectly nice $500 Beovox 5000s

Mike 

Mike,

You said:-

As for the manuals, are there no free resources? In the old computer world, we have bitsavers, which is all free:

http://www.bitsavers.org/
 
" As of Mar, 2008 there are over 13,300 documents containing over 1,228,400 pages in the archive."

I come from the computer world where such resources are freely available, but in the B&O world, finding technical information can be more of a challenge..

camshaft:

Chris, is the comparison between the 5000's and the pentas really split 50/50 between the members?  I always thought it was Graham(Joeyboygolf) vs. everyone else 

Well that's what we all thought but after many heated debates a poll was started to finally put it to bed and the results were 50/50 as far as I can remember. I've done a search for the results but can't find them unfortunately.

Chris.

Here they are Chris, Speaker Shootout!

Andy T.

Medogsfat:

MS150's are often touted as being the best passive speakers ever built by B&O and are the recommended ones for the Beomaster 8000. Most will now require refoaming of the Bass & Midrange drivers though if not already done. They tend to be quite expensive even in poor condition. If you find some (as with all this speaker range) always check that the drivers haven't been replaced with so called equivalent ones

Well I picked up a pair on ebay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=270236535643

Original owner, untouched for 20 years, so in need of some TLC, but GBP140 / $270 seemed reasonable (?) - some research showed good ones go for much more. Refoam if necessary, recap, they'll be spectacular

Thanks for the hints.

Mike
 

I don't see where this thread ever got updated.

barry

Hello Martin,

I've bought a set of passive Penta's from a B&O dealer in The Netherlands. they've replaced the midrange units by Haes units made in Hungary (!). They told me that it was original B&O. I phoned them and they sad that B&O themselfs are not manufactoring the units and SEAS or any other factory no longer make the units. Haes units fits and thats it! I repaired the contacts by soldering them but one of the speakers have no midrange sound at all while I made the contacts properly. I am going to take them all out and test then one by one.  Do you know if the Haes units are junk? And what can I do about it? Do you have a upgrade kit with new caps etc. for the crossover?

Many thanks and best regards,

René Stam

Netherlands

René,
Welcome to Beoworld !

I am not familiar with the Haes drivers so I'm afraid I cannot advice.
You can measure their DC resistance and compare to those in the other
cabinet but it would be a bit strange if all midranges in one cabinet
had gone bad at the same time.

Yes, a cap kit is available. PM me for details, but try to locate the fault first.
Eventually, swap the crossover board from the other cabinet to help diagnose.

Martin

Thanks for your answer, I've send you a e-mail for the kit. I am going to test the units later. Greetings, René.

Hello Martin, I think the e-mail didn't succeed. I want to order a cap-kit for my 2 passive penta's (earlier I ordered a kit for my BG8000, do you remember?) I can pay you with PayPal. My e-mail adress is ***. Please answer so I can repair the set. Best regards, René Stam.

EDIT: Email address removed (anti-spam) and kept for reference.
Martin
Beoworld Moderator

You have mail !

Martin